1. Field of the Invention
The present invention relates generally to a mobile communication system, and more particularly, to an apparatus and method for controlling transmission antenna arrays for a high-speed physical downlink shared channel (HS-PDSCH), which coexists with a dedicated physical channel (DPCH), for taking into consideration a soft handover of a mobile communication system.
2. Description of the Related Art
An HS-PDSCH used in a wideband code division multiple access (WCDMA) system using an asynchronous mobile communication method among third generation mobile communication methods is a channel shared by a plurality of users or user equipments (UEs). In other words, the HS-PDSCH is assigned to a plurality of UEs to transmit packet data in units of 2-ms radio sub-frames to each UE. In the HS-PDSCH, packet data can be transmitted at different rates, and a weight on a transmission antenna array can be adjusted in units of slots as in a dedicated channel (DCH) set between a base station and a UE in the WCDMA system. The radio sub-frame is a unit in which high-speed packet data is transmitted in the WCDMA system and has a length of 2 ms. Five radio sub-frames exist in a single radio frame. The radio frame is a basic unit in which a signal is transmitted in the WCDMA system and has a length of 10 ms. Fifteen slots constitute a single radio frame.
The HS-PDSCH transmits only user data. For weight control of the HS-PDSCH, when the HS-PDSCH is allocated to a UE, simultaneously, a downlink dedicated physical channel (DL-DPCH) is allocated to the UE. The DL-DPCH is used for the weight control of the HS-PDSCH. The HS-PDSCH transmissions can be performed during multiple sub-frames or a single sub-frame to a single UE or user. The time at which a frame is to be transmitted to a plurality of UEs is determined via scheduling of a higher layer. The scheduling result is transmitted to each UE using a high-speed shared control physical channel (HS-SCCH) corresponding to the HS-PDSCH.
Operations of the HS-PDSCH, the HS-SCCH, and the DL-DPCH are described in detail in TSG-RAN WG1 Specification #25.314 (3GPP TS 25.214) made by Third Generation Partnership Project (3GPP) standardization committee. Specifications are provided on an official file service site, i.e., www. 3gpp.org.